Field
The exemplary embodiments described herein relate to computed tomography (CT) systems. In particular, exemplary embodiments relate to a magnetic field actuation of X-ray detectors in a CT scanner.
Description of the Related Art
The X-ray beam in most computed tomography (CT) scanners is generally polychromatic. Yet third-generation CT scanners generate images based upon data according to the energy integration nature of the detectors. These conventional detectors are called energy-integrating detectors and acquire energy integration X-ray data. On the other hand, photon-counting detectors are configured to acquire the spectral nature of the X-ray source, rather than the energy integration nature. To obtain the spectral nature of the transmitted X-ray data, the photon-counting detectors split the X-ray beam into its component energies or spectrum bins and count the number of photons in each of the bins. The use of the spectral nature of the X-ray source in CT is often referred to as spectral CT. Since spectral CT involves the detection of transmitted X-rays at two or more energy levels, spectral CT generally includes dual-energy CT by definition.
Spectral CT is advantageous over conventional CT because spectral CT offers the additional clinical information included in the full spectrum of an X-ray beam. For example, spectral CT facilitates in discriminating tissues, differentiating between tissues containing calcium and tissues containing iodine, and enhancing the detection of smaller vessels. Among other advantages, spectral CT reduces beam-hardening artifacts, and increases accuracy in CT numbers independent of the type of scanner.
Conventional attempts include the use of integrating detectors in implementing spectral CT. One attempt includes dual sources and dual integrating detectors that are placed on the gantry at a predetermined angle with respect to each other for acquiring data as the gantry rotates around a patient. Another attempt includes the combination of a single source that performs kV-switching and a single energy-integrating detector, which is placed on the gantry for acquiring data as the gantry rotates around a patient. Yet another attempt includes a single source and dual energy-integrating detectors that are layered on the gantry for acquiring the data as the gantry rotates around a patient. All of these attempts at spectral CT were not completely successful in substantially solving issues, such as beam hardening, temporal resolution, noise, poor detector response, poor energy separation, etc., for reconstructing clinically viable images.